The use of tumour volumetrics to assess response to therapy in anticancer clinical trials

Abstract

Serial evaluations of tumour burden using imaging, mainly computed tomography and magnetic resonance imaging, form the basis for assessing treatment response in many clinical trials of anticancer therapeutics. Traditionally, these evaluations have been based on linear measurements of tumour size. Such measurements have limitations related to variability in technical factors, tumour morphology and reader decisions. Measurements of entire tumour volumes may overcome some of the limitations of linear tumour measurements, improving our ability to detect small changes reliably and increasing statistical power per subject in a trial. Certain technical factors are known to affect the accuracy and precision of volume measurements, and work is in progress to define these factors more thoroughly and to qualify tumour volume as a biomarker for the purposes of drug development.

Volumetric assessment of lymph node metastases in patients with non-seminomatous germ cell tumors treated with chemotherapy

“…Other limitations include patient-related factors (positioning, anatomy) and technical factors (slide thickness, contrast administration). 11,12 Our study tries to overcome some of these issues with the use of a volumetric measurement, which has demonstrated a good correlation and accuracy with the actual size of the lesion. [13][14][15] Reproducibility, accessibility, and accuracy are waiting to be demonstrated in clinical practice.…”

“…Nevertheless, studies have employed software and semiautomated techniques facilitating this work and volumetry measurements should be applied under expert supervision to avoid overestimation errors. [12][13][14][15][16][17][18] The number of lesions and tumours examined for each patient depends on the response rate, and most of the recommendations are arbitrary. Usually, the number of lesions to be measured for the assessment is 2 lymph nodes and 2 targets per organ (up to 5 targets in total).…”

Positron emission tomography/computerized tomography for tumor response assessment—a review of clinical practices and radiomics studies

“…Both RECIST and WHO criteria are linear measurements of tumor size, which have limitations related to technical variability, tumor morphology, and reader decisions. With the thin-section CT, it is possible to measure tumor volume using segmentation methods with adequate spatial resolutions (13,14), which overcomes some of the limitations of linear measurements. Changes in attenuation in contrast-enhanced CT (CECT) have been shown to correlate better with response than changes in tumor size in hepatocellular carcinoma (15) and gastrointestinal stromal tumor (16).…”

Editors’ pick 2012

“…Goldmacher & Conklin reviewed which tumour size measurements are the best biomarkers in assessing therapeutic response. Serial assessments of tumour burden is of paramount importance, be it in a clinical trial or as standard of care.…”